NRLF 


5bD 


LIBRARY 


UNIVERSITY  OF  CALIFORNIA, 


RECEIVED    BY   EXCHANGE 


Class 


The  Drop  Weights  of  Twenty  Non-associated 

Liquids  and  the  Molecular  Weights 

Calculated  for  them 


DISSERTATION 


SUBMITTED    IN    PARTIAL    FULFILMENT    OF    THE    REQUIREMENTS    FOR 

THE    DEGREE    OF     DOCTOR    OF    PHILOSOPHY    IN    THE 
FACULTY     OF     PURE     SCIENCE    IN    COLUMRIA     UNIVERSITY 
IN    THE    CITY    OF    NEW    YORK 


BY 


GARABED    K.    DAGHLIAN 

New  York  City 

1911 


GOTCHNAG    PUBLISHING    CO 
NEW  YORE.     N.    Y. 
1911 


The  Drop  Weights  of  Twenty  Non-associated 

Liquids  and  the  Molecular  Weights 

Calculated  for  them 


DISSERTATION 


SUBMITTED    IN    PARTIAL    FULFILMENT    OF    THE    REQUIREMENTS    FO1 

THE    DEGREE    OF    DOCTOR    OF    PHILOSOPHY    IN    THE 
FACULTY     OF     PURE     SCIENCE    IN    COLUMBIA     UNIVERSITY 
IN    THE    CITY    OF    NEW    YORK 


BY 

GABABED    K.    DAGHLIAN 

New  York  City 

1911 


GOTCBNAG     PUBLISHING    CO 
NEW  YORE.    N.    Y. 
1911 


ACKNOWLEDGMENT 

Professor  J.  Livingston  R.  Morgan  suggested  and  directed  this  work.  The 
author  begs  to  tender  to  Professor  Morgan  his  sincere  thanks  for  the  assistance, 
advice  and  encouragement  accorded  him  during  the  work. 

G.  K.  D. 


226916 


CONTENTS 

Page 

Object  of  the  Investigation 5 

Apparatus  and  Method 5 

Standardization  of  the  Apparatus 6 

Twenty   New  Liquids    9 

Discussion  of  Results    17 

Conclusions .  19 


OBJECT  OF  THE  INVESTIGATION 

The  object  of  this  work  has  been  to  apply  the  principles  arrived  at  by  former 
workers  in  drop  weights  to  further  non-associated  liquids.  They  proved,  first,  that 
the  drop  weight  of  a  liquid,  measured  under  proper  conditions,  is  proportional  to 
its  surface  tension ;  and  consequently  can  be  substituted  in  place  of  surface  tension 
in  Eotvos'  formula  as  modified  by  Ramsay  and  Shields. 


where  y  stands  for  surface  tension  as  measured  by  capillary  rise,  M  for  molec- 
ular weight,  d  for  density  at  temperature,  t  of  the  liquid,  and  t c  the  critical  tem- 
perature. Second,  they  proved  that  this  method  is  a  great  deal  more  accurate  than 
surface  tension  method. 

APPARATUS  AND  METHOD 

The  apparatus  used  has  been  devised  and  improved  into  its  present  form  by 
Professor  Morgan.  For  a  detailed  description  see  Jour.  Am.  Chem.  Society, 
March,  1911. 

Its  essential  part  consists  of  a  U  shaped  tube  with  a  capillary  bore,  one  end 
of  which  is  carefully  ground  to  a  diameter  of  5.8  mm.,  and  terminates  with  a 
smooth  circular  surface  perpendicular  to  the  axis  of  the  tube,  and  the  bore  of  0.2 
mm.  being  in  the  centre.  The  other  leg  of  this  syphon  tube  dips  in  a  small  vessel 
which  contains  the  liquid  worked  with,  so  that  by  applying  gentle  suction  at  the 
other  end  the  liquid  rises  in  the  tube  and  is  syphoned  over  into  another  small 
weighing  vessel,  which  is  fitted  air-tight  at  the  tip,  forming  drops.  The  apparatus 
is  so  designed  that  these  two  small  vessels  can  be  removed  and  replaced  readily; 
so  allows  work  at  different  temperatures;  and  is  so  arranged  that  it  can  be  in  a 
water  bath  at  the  desired  temperature.  These  baths  are  heated  with  the  vapor 
of  boiling  ether  or  chloroform  or  can  be  cooled  by  allowing  tap  water  to  run 
through  them. 

The  liquid  at  all  times  is  under  perfect  control,  being  regulated  by  means 
of  a  rubber  bulb  which  is  connected  by  capillary  rubber  tubing  to  the  weighing 
vessel  through  the  ventilation  tubes. 

The  U  shaped  siphon  tube  which  is  called  the  "tip"  is  cleaned  before  starting 
a  new  liquid  by  running  through  it  potassium  dichromate  solution  and  sulphuric 


6 


acid,  water,  alcohol,  ether,  and  dry  air.  The  supply  vessel  is  then  half  rilled  with 
the  liquid  and  a  drop  allowed  to  form  and  hang  for  five  minutes,  after  the  constant 
temperature  is  attained,  to  saturate  the  vessel  with  the  vapor,  and  then  a  definite 
numbe*  of  drops  (15,  25,  30)  is  run  into  the  weighing  vessel.  This  with  its  con- 
tents is  then  weighed  after  the  apparatus  is  removed  from  the  bath.  A  number 
of  such  determinations  are  made.  Then  a  number  of  determinations,  "blanks," 
are  made  with  only  5  drops  ;  but  the  sixth  drop  is  allowed  to  hang  without  falling 
long  enough  to  make  the  time  of  this  determination  equal  to  that  of  the  other  with 
more  drops.  In  this  way  any  evaporation  through  the  ventilation  tubes,  or  con- 
densations, or  evaporation  from  the  drops  before  falling,  or  evaporation  back  to 
the  hanging  drop,  etc.,  are  made  equal  in  the  two  sets  of  determinations.  By  sub- 
tracting the  average  weight  of  one  set  from  that  of  the  other  we  get  the  weight 
of  number  of  drops  equal  to  the  difference  of  those  taken  in  the  two.  And  that 
gives  us  the  weight  of  single  drop  at  the  temperature  of  observation. 

Sometimes,  when  the  liquid  has  a  very  high  boiling  point,  at  low  temperature, 
it  is  only  necessary  to  use  the  weight  of  the  empty  vessel  as  blank. 

Weight  of  a  single  drop  is  given  in  milligrams  and  is  indicated  by  w. 

w\—:\      is  called  the  molecular  drop  function  and  we  will  indicate  it  by/(M). 
L  a  J 

STANDARDIZATION  OF  THE  APPARATUS 

We  mean  by  this  the  testing  to  see  if  a  tip  of  this  size,  5.8  mm.,  will  give 
uniform  results  with  the  test  liquids  as  tips  of  different  sizes  with  which  work  has 
been  done  before  ;  and  at  the  same  time  to  determine  the  constant  of  this  particular 
tip.  The  test  liquids  are  aniline,  benzene,  pyridene  and  quinoline.  A  number  of 
determinations  have  been  made  with  each  one  of  these  at  two  temperatures. 
Weight  of  single  drop  has  been  obtained,  and  k  has  been  calculated  for  each  liquid 
at  both  temperatures  from  equation 


in  which  w  and  t  have  been  measured  and  observed,  and  d  and  /      have  been 
taken  from  former  determinations. 

Table  I  gives  the  equations  for  densities,  the  critical  temperatures  (by 
Higgins),  and  the  molecular  weights  of  the  test  liquids  as  has  been  used  in  the 
following  calculations  ; 

TABLE   I 

/         Mol.  Wt. 


Aniline  dt  =  1.038797  —  0.0008605  /  425.8  93.00 

Benzene  dt  =  0.900214  —  0.0010659  /  288.4  78.00 

Pyridene  dt  =  1.001500  —  0.0010018  /  347.0  79.00 

Quinoline  dt  —  1.109894  —  0.0008034  /  520.4  129.00 


Carbon  tetrachloride  is  one  of  the  usual  test  liquids.  But  on  account  of 
the  great  size  of  this  tip  and  the  very  smartl  volume  of  the  drop  that  liquid  was 
omitted.  It  is  clear  that  whenever  a  drop  falls  abruptly  and  not  by  its  own 
weight,  the  drop  weight  is  too  large.  Carbon  tetrachloride  has  a  very  small 
surface  tension  and  a  large  density ;  for  this  reason  the  drop  falls  abruptly  and  so 
weighs  heavier.  The  tip  being  very  large,  too  much  liquid  in  weight  is  contained 
in  the  drop  volume  for  the  surface  tension  of  the  liquid  to  be  able  to  hold  without 
breaking.  As  soon  as  this  breaking  takes  place  before  the  maturity  of  the  drop, 
the  falling  part  carries  with  it  apparently  part  of  the  liquid  which  would  remain 
on  the  surface  of  the  tip  as  remaining-drop  if  it  had  not  been  snatched  unduly. 
On  tips  still  larger  carbon  tetrachloride  gives  proportionately  larger  values.  But 
on  smaller  tips  it  is  possible  to  control  the  drop  as  the  weight  of  liquid  contained 
in  the  drop  is  not  too  large  for  the  tension  of  the  bounding  surface  to  break  it 
prematurely. 

The  experimental  values  for  the  test  liquids  are  given  in  Table  II. 


TABLE   II 


Aniline 


Benzene 


Pyridine 


Quinoline 


Temp. 

34.30 
34.20 
34.35 
34.30 

Wt.  vessel 
-1-  liquid 

11.0954(10)1 
11.0960  » 
11.0960  » 
11.0950  »  J 

36.05 
36.05 
36.35 

11.0871(15)^) 
11.0868  » 
11.0868  »  J 

59.575 

11.0472  »  1 

59.525 

11.0474  » 

59.525 

11.0467  »  J 

23.025 
22.750 

11.2548(15)' 
11.2550  » 

23.125 

11.2544  » 

22.825 

11.2553  » 

58.325 
58.425 

10.6389(25)-| 
10.6384  »  j- 

58.400 

10.6385  »  J 

22.375 
22,275 

10.4846(15)  ) 
10.484tf  »  ) 

Average  wt. 


Wt.  vessel 
4-  5  drops 


Average 
Average  wt.      temp. 


lin,71   10.7883) 
n-°471  10.7882  f 


11  2549  10'8484  i 
U™  '   10.8482  J 


Drop  wt. 


11.0956  10.6440(0)   10.6440     34.28       45.16 


10.7955     36.15       29.14 


10.7883     59.64       25.88 


10.8483     22.93       40.66 


9.9343     58.39     35.215 


10.6386 


9.9346 
9.9340 


80.4846     9.7525(0)     9.7525     22.33      48.81 


M 

f 

w 

d 

/(M) 

k 

93 

34.3 

45.16 

1.0093 

921.20 

2.3898 

78 

36.15 

29.14 

0.8617 

587.47 

2.3857 

59.54 

25.88 

0.8368 

532.06 

2.3874 

79 

22.93 

40.66 

0.9875 

759.31 

2.3872 

58.39 

35.215 

0.9430 

674.23 

2.3858 

129 

22.33 

48.725 

1.09195 

1175.17 

2.3882 

8 

In  Table  III  are  given  the  results  of  calculation  from  these  experimental 
values. 

TABLE    III 


Aniline 
Benzene 

Pyridene 

Quinoline 

The  meaning  of  k  for  any  one  liquid  is  this:  If  we  work  with  one  of  the 
liquids  at  different  temperatures,  and  calculate  molecular  drop  function  for  each 
temperature,  when  we  plot  a  curve  taking  these  for  ordinates  and  for  abscissas 
tc  -/-6,  then  we  have  a  straight  line  for  our  curve  which  makes  an  angle  equal  to 
arc  tan  k  with  the  axis  of  x.  Moreover  if  we  proceed  likewise  with  other 
liquids,  we  get  a  straight  line  for  each  liquid  equally  inclined  to  the  axis  of  xt 
only  they  intercept  the  axis  of  x  at  different  distances  from  the  origin.  When 
/(M)  plotted  in  this  way  does  not  give  a  straight  line  for  the  curve,  that  liquid 
is  called  to  be  associated* 

The  average  k  is  called  the  constant  of  the  tip.  For  reason  to  be  mentioned 
later  we  will  adopt  as  the  constant  of  this  tip  k  value  for  benzene  which  is  2.3866. 

In  working  with  these  liquids  special  care  had  to  be  exercised  with  aniline 
to  have  it  freshly  distilled,  and  also  to  see  that  the  capillary  bore  of  the  tip  is 
washed  with  ether  and  dried,  by  passing  dry  air  through  it  for  10-15  minutes, 
between  determinations.  Otherwise  the  successive  determinations  give  larger  and 
larger  values.  When  pure,  aniline  is  almost  colorless,  and  standing  for  even  a 
day  causes  it  to  color  a  little.  In  all  cases  the  drops  were  formed  fast,  then  checked 
before  falling,  and  allowed  finally  to  fall  slowly  and  of  their  own  weight.  Causing 
a  drop  to  fall  rapidly  always  gives  a  heavier  drop,  for  it  does  not  fall  of  its  own 
weight  alone,  but  is.  forced  out  and  takes  with  it  more  liquid  than  it  should. 


*See  also  page  (12) 


9 
TWENTY  NEW  LIQUIDS 

The  investigation  of  twenty  new  liquids  by  drop  weight  method  forms  the 
main  part  of  this  work.  These  liquids  were  of  greatest  attainable  purity.  Brom- 
benzene  and  iodobenzene  were  specially  prepared  in  the  laboratory;  diphenyl 
methane  was  from  Eimer  and  Amend,  redistilled  and  recrystallized  just  before 
the  determination  was  made;  isobutylacetate,  m-xylene,  o-xylene,  p-xylene,  one 
sample  of  mesitylene,  bromine  and  phosphorus  trichloride  were  from  Kahlbaum, 
usually  redistilled  just  before  using;  while  the  others,  including  one  sample  of 
mesitylene  were  especially  prepared  for  this  work  by  the  Hoffman  and  Kropff 
Chemical  Co.  (619  Kent  Avenue,  Brooklyn,  N.  Y.),  and  used  directly. 

Experimental  results  are  given  below  in  Table  IV.  All  the  individual  results 
are  not  given,  only  those  where  the  determination  and  the  blank  were  at  the  same 
temperature  being  included  in  the  tables.  But  the  mean  of  all  determinations  is 
within  a  very  small  error  equal  to  the  values  given. 


Brombenzene 


Temp. 


Wt.  Vessel 
4-  liquid 


TABLE   IV 


Wt   Vessel 
Average  wt.       +5  drops 


37.90  11.5863(25) ) 

38.40  11.5870  »  C  11.5867 

31.55  11.5867  »  ) 

59.625  11.5210  » 

59.700  11.5207  » 


..52085 


Bromine 

0 

0 

11.4376(15)) 
11.4380  »  C 

0 

114385  »  ) 

11.43803 


Carbon  disulphide 

20.15    11.1733(15)^ 

20.35    11.1718  »  C  11.17337 

19.90    11.1750  »  ) 


Cymene 
18.95 
18.75 
18.35 
59.45 
59.45 


11.0995(15)) 
11.1015    »    C  11.1009 
11.1018    »    ) 
11.0406    » 
1L0408    » 


10.8345 
10.8352 

10.8252 
10.8247 


10.9141 
10.9146 


10.8190 
10.8190 


10.7963 
10.7968 
10.7972 

10.7774 


Average 

Average  wt.  temp.  Drop  wt. 

10.83485  38.3  37.593 

10.82495  59.67  34.795 

10.91435  0.00  52.368 

10.81900  20.13  35.437 

10.79677  18.7  30.413 

10,7774  59.45  26.33 


10 


TABLE  IV   (Cont) 


Dimethyl  aniline 

Wt.  Vessel 
Temp.                    -f  liquid 

21.45         11.2381(15) 
21.55         11.2379    » 
59.50         11.1684    » 
59.55         11.1684    » 
59.45         11.1689    » 
59.50         11.1679    » 

Diphenyl  methane 
59.05         11.2108(15) 
59.00         11.2113    » 
58.875       11.2109    » 

Ethyl  benzene 

Average  wt. 

11.2380 
i-   11.1684 

t   11.2110 

Wt.  Vessel 
-f-  5  drops 

10.8419     | 
10.8418     | 

10.8196     ) 
10.8192 
10.8194     ) 

10.6440(0) 

20.90 

11  1154^15^ 

"V 

21.10 

11.1155    » 

f 

11 

.11545 

10. 

8022 

59.40 
59.60 

11.0528    » 
11.0519    » 

} 

11 

.0523 

10. 

7846 

Ethyl  aniline 

35.80 
35.80 
35.80 

11.2152(15) 
11.2150    » 
11.2154    » 

! 

11 

.2152 

10.8355 
10.8355 
10.8352 

1 

58.70 

11.1760    » 

^ 

10. 

8224 

^ 

L 

1  760 

y 

58.70 

11.1760    » 

> 

•  -I-  1  \J  \J 

10. 

8224 

> 

Ethylene  chloride 

34.20 
34.10 

11.1483(15) 
11.1484    » 

I 

11 

.14843 

10. 

8166 

1 

34.07 

11.1486    » 

\ 

10. 

8167 

* 

60.00 

11.4258(26) 

11.4258 

10.8404(6) 

Ethylidene  chloride 

34.125 
34.100 

11.0427(15) 
11.0422    » 

i 

11 

.04263 

10. 

7822 

1 

34.050 

11.0430    » 

i 

10. 

7822 

' 

56.90 

11.2097(20) 

11 

.2097 

10. 

8683(10) 

Flourbenzene 

9.30 

12.8962(20) 

) 

9.30 

12.8965    » 

12 

.8962 

12. 

2747  i 

(0) 

9.30 

12.8960    » 

) 

34.50 

12.9630(25) 

^ 

12. 

4122 

> 

34.50 

12.9631    » 

j 

12 

.96316 

12.4126      £• 

34.50 

12.9634    » 

12. 

4125 

) 

Average  wt. 

10.84185 
10.8194 


10.8022 
10.7846 

10.8354 
10.8225 

10.81665 
10.8404 

10.7822 
10.8683 

12.2747 


Average 
temp. 


21.5 


59.5 


10.6440         59.0 


21.0 
59.5 

35.8 

58.7 

34.1 
60.0 

34.10 
56.9 

9.3 


12.4124         34,5 


Drop  wt. 

39.15 
34.9 


37.8 

31.325 
26.776 

37.98 
35.35 

33.178 
29.27 

26.043 
22.76 

31.077 
27.537 


11 


TABLE  IV    (Con/.) 


lodobenzene 


Wt.  Vessel 


Wt.  Vessel 


Average 


Temp.                  4"  liquid 

23.5           11.9297(50) 
59.6           10.9270(30) 

Isobutyl  acetate 
23.8           10.5152(30) 
59.375       10.2991(25) 
59.275       10.4075(30) 

Mesitylene 
23.55         11.0844(15) 
23.50         11.0844    » 
57.20         11-0452    » 
57.40         11.0440    » 

Average  wt. 

11.9297 
10.9270 

10.5152 

i 

11.0844 
11.0446 

+  5  drops 

10.1876(10) 
10.1441(10) 

10.0082(10) 
9.8680  (5) 
9.9766(10) 

10.7812     | 
10.7812     ) 
10.7787     ) 
10.7785     > 

Average  wt. 

10.1876 
10.1441 

10.0082 

10.7812 
10.7786 

temp. 

23.5 
59.6 

23.8 
59.3 

23.5 
57.3 

Drop.  wt. 

43.55 

39.085 

25.35  ; 
21.55 

30.32 
26.60 

Metaxylene 

29.90 

10.2095(15) 

10. 

2095 

9.9057 

9 

.9057 

24 

.9 

30.38 

58.9 

10.1529    » 

10. 

1529 

9.8888 

9.8888 

58.9 

26.41 

Methyl  aniline 

24.65 
24.55 

10.8230(25) 
10.8232    » 

f 

10. 

8231 

9.9660 
9.9659 

i 

9 

.9659  ' 

24 

.6 

42.86 

59.7 
59.7 

11.2219    » 
11.2217    » 

i 

11. 

2218 

10.8378 
10.8382 

t 

10 

.8380 

59 

.7 

38.38 

O*  thoxvlene 

23.85 
23.85 

10.2345(15) 
10.2346    » 

i 

10.23455 

9.9144 
9.9144 

t 

9 

.9144 

23 

.85 

32.05 

59.30 

10.1756    » 

j 

10. 

1753 

9.8965 

9 

.8965 

59 

.4 

37.88 

59.50 

10.1750    » 

> 

Paraxylene 

37.9 

11.3678(25) 

11.3678 

10.7921 

10 

.7921 

37 

.9 

30.785 

59.2 
59.195 

11.3079    » 
11.3083    » 

} 

11.3081 

10.7820 
10.7819 

! 

10 

.78195 

59.2 

26.308 

Phosphorus  trichloride 

35.57         11.5517(30)  \ 

35.60    11.5515  »  V  11.5514 

35.62    11.5510  »  ) 


10.9567(10) 
10.9567  » 


1.9567 


35.6 


29.73 


Toluene 

36.05 
36,00 

11.0809(15)^ 
11.0808  »  ] 

f  '"«»  !S!e  ! 

10.7916         36.0           28.925 

59.1 
59.3 

11.0425  >>  ] 
11.0421  »  J 

f  »«•  ESS  ! 

10.78144       59.2           26.075 

12 

It  has  been  shown  by  Morgan  that  the  value   k  'B  found  -from  the  equation 


for  any  one  tip,  with  benzene  (where  288.5  is  the  observed  critical  temperature), 
can  be  used  as  the  standard  constant  of  the  tip  worked  with.  And  that  from  this 
£B  using  it  in  the  equation 

/(M)  =  £B  (tc-(-e); 

for  any  other  liquid,  M  is  shown  to  be  the  normal  molecular  weight  of  that  liquid 
when  the  calculated  value  of  t  c  from  w,  M,  and  d  for  the  new  liquid  at  different 
temperatures,  t,  is  the  same;  for  the  constancy  of  t  c  independent  of  temperature 
shows  that  £B  is  also  the  correct  temperature  coefficient  of  the  molecular  drop 
function  of  that  liquid,  and  hence  it  is  non-associated,  just  as  the  standard  liquid 
benzene  is  non-associated. 

Further,  it  is  plain  that  surface  tension  in  dynes  per  centimeter  of  any  liquid 
can  be  calculated  directly  from  drop  weight  in  milligrams  at  the  same  temperature 
by  aid  of  the  proportion  7  :  w  =  £'B  :  £B  where  £H  is  the  corresponding  value 
for  the  surface  tension  as  found  from 


and  so  by  using  these  two  values  £'B  and  £B  comparisons  at  different  tempera- 
tures can  be  made  of  drop  weight  and  surface  tension. 

We  can  look  at  this  also  from  the  graphical  side.  It  was  pointed  out  that 
graphical  meaning  of  k  is  that  it  is  the  slope  of  a  certain  curve,  and  that  this  slope 
changes  in  value  according  to  the  size  of  the  tip.  If  we  strike  a  tip  of  just  proper 
size  so  that  its  k  is  the  same  as  the  k  obtained  from  surface  tension  (which  is 
about  2.12)  then  drop  weights  of  a  liquid  from  that  tip  in  milligrams  is  equal  to 
the  surface  tension  of  that  liquid  in  dynes  per  centimeter  at  the  same  temperature. 

It  must  be  remembered  here  that  drop  weight  in  essence  is  a  more  directly 
experimental  value  than  surface  tension  by  capillary  rise,  for  the  former  is  simply 
a  singly  determined  weight,  while  the  latter  is  equal  to^2  r  h  (d-d')  where  r  stands 
for  the  radius  of  a  small  capillary  bore,  assumed  to  be  constant,  h  for  the  height 
of  the  column  of  liquid  rising  into  the  capillary  bore,  which  is  burdened  with  an 
error  of  6-9%  due  to  the  volume  of  the  meniscus,  and  d-d'  for  the  difference  of 
the  density  of  the  liquid  and  density  as  vapor  at  that  temperature.  This,  perhaps, 
will  serve  to  account  for  the  variable  results  below  of  surface  tension  as  obtained 
from  capillary  rise. 

Below  in  Table  V  are  given  the  values  of  the  function  /(M)  and  \c  as  cal- 
culated from  drop  weights,  together  with  the  same  values,  as  far  as  they  can  be 
found  in  the  literature,  calculated  from  capillary  rise.  Each  liquid  is  taken  as  a 
subdivision  of  Table  V,  and  the  molecular  weight  and  the  formula  for  the  density 
as  used  in  the  following  calculations  are  given;  also  the  observed  tc.  Of  the 
columns  the  first  is  the  temperature,  and  the  others  are  in  order  drop-weight  or 
surface-tension,  density,  molecular  function,  and  tc  calculated. 


13 

TABLE  V 

1. 

Brombenze, 
38.3 

M=156.96, 
37.593 

4=1.5203—0.001282,     .    , 
1.4713             845.6 

^f™ 

59.67 

34.794 

1.4438            792.557 

397.8 

2. 

Bromine, 
0.0 

52.368 

,4=3.18718,        /=:302.2 
3.1872         '   712.17 

304.4 

10.6 

Ramsay  and   Aston,     £B=2.12112 
40.27                   3.152               552.08 

276.9 

46.0 

34.68 

3.031               487.98 

282.1 

78.1 

29.51 

2.917               426.09 

285.0 

3. 

Carbon  disulphide,      M=76, 
20.13           35.440 

,14,     4=1.29215—  0.0013025/,     /=275(*) 
1.26594           544.05               254.1 

4. 

Cymene, 
18.69 

M=134.112,      4=0.862—0.0008044  Gf-11.9), 
30.414                 0.85554           883.52 

394.9 

59.45 

26.330 

0.82376           785.20 

394.5 

Renard 

and  Guye,     £p=2.1108 

11.9 

27.98 

0.862               809.38 

401.3 

31.7 

26.19 

0.846               767.13 

401.1 

54.8 

23.95 

0.828               711.65 

397.95 

74.5 

22.16 

0.812               667.08 

396.5 

91.8 

20.60 

0.798               627.35 

395.0 

108.9 

19.18 

0.784               591.04 

394.9 

117.0 

18.45 

0.778               571.57 

393.7 

134.9 

16.97 

0.762               532.96 

393.4 

146.5 

15.94 

0.751               505.48 

392.0 

163.4 

14.60 

0.735               469.68 

391.9 

172.8 

13.92 

0.726               451.50 

392.7 

5. 

Dimethyl  aniline,      M=121 
21.5             39.615 

.098,     4=0.9589—0.000825  (/f-16.7),     /  =:414.45 
0.95494           999.94               446.5 

59.5 

34.90 

0.92359           900.74 

442.9 

22.7 

Dutoit  and  Friderich,     £B=2.10124 
35.31                   0.9540             891.5 

453.0 

43.5 

32.81 

0.9368             838.6 

448.6 

76.7 

29.24 

0.9086             762.5 

445.6 

99.0 

26.80 

0.8895             708.3 

442.1 

(*)  also  272.96,     277.63,      271.8,     279.6,     278,05 


14 
TABLE  V   (Con/.) 

Renard  and  Guye,     £B=2.1108 

10.9 

36.27 

0.964               909.75 

447.9 

41.0 

33.12 

0.939               845.41 

447.5 

55.0 

31.53 

0.927               811.76 

445.6 

78.9 

28.84 

0.907               753.38 

441.8 

96.0 

27.04 

0.892               714.26 

440.4 

108.8 

25.71 

0.882               684.25 

438.9 

126.7 

23.91 

0.866               644.16 

437.9 

134.8 

23.12 

0.858               626.26 

337.5 

154.0 

21.20 

0.840              582.87 

436.2 

165.0 

20.18 

0.828               560.61 

436.6 

175.5 

19.19 

0.822              535.28 

435.1 

6. 

Dephenyl  methane,      M=16£ 

1.1,     4=1.0126—0.0007914  (, 

f-11),     /c=497 

59.0 

37.80 

0.9745           1171.26 

555.8 

Dutoit  and 

Friderich,      £B=2.10124 

108.3 

27.86 

0.9209             931.4 

557.5 

210.2 

19.11 

0.8438            677.1 

538.4 

7. 

Ethyl  benzene, 

M=106.08, 

^=0.88316—0.0008333^     , 

f  =346.4 

c 

21.9 

31.325 

0.86566           772.83 

350.8 

59.5 

26.775 

0.83358          681.13 

351.3 

8. 

Ethyl  aniline, 

M=121.098, 

4=0.9796—  0.000831/,     /=:425.4 

35.8 

37.89 

0.9488             862.06 

444.90 

58.7 

35.35 

0.9310             907.51 

444.96 

Dutoit  and 

Friderich,     kB=2.10124 

7.4 

37.26 

0.9738             927.9 

455.0 

107.8 

22.89 

0.8886             698.4 

446.2 

210.0 

16.76 

0.7996             477.6 

443.3 

9. 

Ethylene  chloride,      M=98.95,     4=1.280149—  0.0015277/ 

(  288.4 
,     f=  ]  289.3 
(  283.3 

34.1 

33.178 

1.22805           618.79 

299.4 

60.0 

29.27 

1.18850           558.09 

299.8 

10. 

(  250.0 
Ethylidene  chloride,      M=98.95,     «/  =1.206951  —  0.0015992/,     t—  -}  254.5 
(  260.0 

34.065 

26.042 

1.1525             506.87 

252.5 

56.8 

22.76 

1.1160             452.56 

252.5 

15 


11. 


12. 


13. 


14. 


TABLE  V    (Cont.) 

Flourbenzene,      M=96.04,       4=1.04655-0.001208*, 

9.3  31.077  1.03435  636.80 

34.5  27.537  1.00537  574.62 


282.1 
281.7 


lodobenzene,      M=203.96,     4=1.8606-001535*,     ^=448.0 

23.5  43.55  1.82445         1010.62  453.0 

59.6  39.08  1.7691  925.73  453.5 

(  288.3 
Isobutyl  acetate,     M=H6.096,    ^=0.8802-0.001065  («-10),    *tf=|295.8 

23.8  25.35  0.86565  664.23  308.1 

59.3  21.55  0.82820  581.54  309.0 


15. 


Mesitylene, 

M=120.1,     d  =0.8746—  0.00081/,     ^36=7.7 

23.5 

30.32 

0.8656 

812.61 

370.0 

57.3 

26.60 

0.8282 

734.21 

370.9 

Dutoit  and  Friderich,     £B=2.10124 

7.4 

27.92 

0.8686 

746.1 

368.5 

108.4 

18.47 

0.7846 

528.9 

360.1 

Renard 

and  Guye,     k 

B=2.1108 

11.4 

28.3 

0.866 

758.23 

376.6 

25.1 

26.7 

0.054 

722.05 

373.2 

36.3 

25.84 

0.845 

703.75 

375.7 

55.4 

23.99 

0.829 

661.74 

374.9 

64.8 

23.29 

0.821 

646.60 

377.1 

74.3 

22.20 

0.814 

619.39 

373.8 

92.2 

20.57 

0.798 

582.01 

373.9 

108.9 

19.03 

0.784 

544.83 

373.0 

127.0 

17.43 

0.769 

509.38 

374.3 

146.6 

15.83 

0.752 

465.98 

373.4 

156.2 

15.02 

0.744 

445.30 

373.2 

Metaxylene, 

M=106.08, 

4=0.874—0 

.000944  (/-10) 

,    *,=346.l 

24.9 

30.38 

0.8599 

752.85 

346.4 

58.9 

26.41 

0.8271 

671.67 

346.3 

Dutoit  and  Friderich, 

15.7             28.97  0.869 

74.9             22.71  0.814 

136.7             16.56  0.759 


714.2 
583.4 
445.8 


361.6 
358.5 
354.8 


16.     Methyl  aniline,      M=107.08, 

24.6  42.86 

59.7  38.38 


TABLE  V    (Con/.) 


351.4 
352.7 
351.6 
350.7 
350.4 
850.2 
3a0.2 
351.5 
351.7 
352.1 

4=0.9944— 0.000801(^-10),     /f=428.6 
0.9827  977.78  440.^3 

0.9546  892.68  440.3 


Renard 

and  Guye, 

kB=2.1108 

10.0 

28.88 

0.874 

707.95 

38.0 

26.06 

0.849 

651.57 

49.0 

24.75 

0.837 

624.47 

63.9 

23.25 

0.824 

592.78 

76.8 

21.94 

0.812 

564.88 

88.0 

20.85 

0.803 

540.82 

99.4 

19.74 

0.792 

516.76 

109.0 

18.94 

0.784 

499.18 

128.3 

17.16 

0.767 

458.93 

136.5 

16.43 

0.759 

442.49 

Dutoit  and  Friderich, 

£B=2.10124 

9.9 

39.19 

0.9947 

886.5 

437.8 

108.5 

26.37 

0.9128 

690.2 

443.0 

210.8 

18.59 

0.8227 

477.7 

444.1 

17. 

Orthoxylene 
23.85 

,      M=106.08, 
32.015 

4=0.8932—  0.0008425/, 
0.8731             785.36 

/f=358.3 
358.9 

59.40 

27.88 

0.8432 

701.07 

359.15 

18. 

Paraxylene, 
37.9 

M=106.08, 
28.785 

4=0.8801—  0.0008468/, 
0.8480             720.0 

/  =344.4 
345.6 

59.2 

26.308 

0.8300 

667.51 

344.9 

19. 

Phosphorus 
35.6 

trichloride,      M 
29.73 

1.5649 

4=1.61275—0 

587.24 

.0013463/, 
287.66 

16.4             28.71 

46.2             24.91 

20. 

Toluene,      M=92.064, 

36.0             28.925 

59.2             26.075 

Ramsay  and  Shields 

1.582  562.3 

1.527  499.8 

4=0.8682—0.0009526(1-15.2),     ^ 


0.8484 
0.8263 

Ramsay  and  Aston, 

15.2  28.18  0.8682 

46.6  24.60  0.8380 

78.4  20.93  0.8080 

132.5  15.53  0.7535 


658.57 
603.75 
kB=2.12112 
631.0 
563.9 
490.8 
382.2 


287.50 

287.80 
(  320.8 
1  320.6 

318.04 

318.02 


318.7 
318.0 
315.8 
319.5 


11 

TABLE  V   (Con/.) 

Renard  and  Guye,     £B=2.1108 

13.1  28.21  0.871  630.65  317.9 

29.1  26.33  0.853  596.87  317.9 

48.0  24.15  0.835  555.29  317.1 

59.0  23.10  0.827  532.93  317.5 

79.0  20.92  0.807  490.01  318.1 

91.5  19.55  0.795  464.48  317.5 

108.9  17.89  0.778  431.21  319.2 

DISCUSSION  OF  RESULTS 

It  will  be  noticed  that  four  liquids  have  been  studied  only  at  one  temperature ; 
viz. :  bromine,  phosphorus  trichloride,  diphenyl  methane,  and  carbon  disulphide. 
In  the  case  of  bromine,  one  temperature  was  considered  sufficient  owing  to  the 
fact  that  practically  the  calculated  tc  agreed  with  observed  one,  and  the  Ramsay 
and  Aston  figures  by  aid  of  capillary  rise,  which  disagreed  with  this,  were  stated 
by  the  authors  to  be  inaccurate.  With  phosphorus  trichloride  at  60°  difficulties 
were  encountered,  possibly  due  to  the  presence  of  water  vapor  in  the  air,  although 
it  was  passed  first  through  drying  tubes,  a  yellow  substance  forming  in  the  ventila- 
tion tube,  and  giving  a  slightly  variable  result,  although  the  mean  value  agreed 
practically  with  that  at  the  lower  temperature  which  leads  to  practically  the 
observed  tc  and  agrees  with  that  found  from  capillary  rise.  With  diphenylme- 
thane  at  23°  it  was  impossible  to  get  satisfactory  results  owing  to  the  fact  that  it 
was  below  its  melting  point,  and  crystallization  in  the  tube  was  hard  to  avoid, 
so  that  checking  results  at  this  temperature  were  difficult  to  obtain.  Since  the 
value  of  tc  at  59°  does  not  differ  greatly  from  the  value  found  by  Dutoit  & 
Friderich  at  108°,  it  was  thought  more  important  to  consider  further  liquids 
rather  than  continue  work  with  this.  Carbon  disulphide  was  used  here  only  to  see 
what  effect  would  be  produced  by  the  known  purity  of  this  sample,  as  compared 
to  that  purified  in  this  laboratory. 

Assuming,  since  in  the  case  of  bromine  and  phosphorus  trichloride,  the  tc 
calculated  agrees  with  the  critical  temperature,  and,  in  the  case  of  diphenyl- 
methane  it  is  in  agreement  with  that  found  at  108°  by  Dutoit  &  Friderich,  that 
these  liquids  are  non-associated,  we  can  conclude  that  all  of  the  liquids  examined 
above,  with  the  exception  of  dimethyl  aniline,  are  non-associated,  for  all,  with 
this  exception,  lead  to  the  same  calculated  value  of  tc  (within  a  very  small  dif- 
ference) at  both  temperatures  of  observation.  In  the  case  of  dimethylaniline 
the  same  downward  trend  is  shown  by  drop  weight  as  is  to  be  noticed  from  the 
results  of  capillary  rise.  It  is  probable  however,  that  this  discrepancy  of  0.8% 
between  59.5°  and  21°  is  due  to  the  decomposition  of  the  liquid,  for  it  darkens 


18 

very  rapidly  on  exposure  to  light,  and  the  low  temperature  observation  was  made 
first  when  the  liquid  was  perfectly  fresh.  Possibly  a  reversed  trend  would  be  the 
case  if  observation  at  high  temperature  was  made  while  the  liquid  was  fresh. 

The  agreement  of  the  calculated  tc  with  the  observed  critical  temperature  was 
found  to  be  very  satisfactory  for  the  following  liquids:  brombenzene,  bromine, 
ethylidene  chloride,  toluene,  phosphorus  trichloride,  paraxylene,  orthoxylene, 
metaxylene,  while  in  mesitylene,  ethylbenzene,  and  iodobenzene  the  discrep- 
ancies are  below  \%  for  the  former,  and  slightly  above  that  for  the  two  latter. 
For  the  other  liquids  the  calculated  t  i.  e.,  the  fictitious  critical  temperature, 
viz.  the  point  6°  below  which,  by  the  formula  /(M)=£B  (t-t-§),  /(M)  would 
be  zero,  is  larger  than  critical  temperature  for  cymene,  dimethyeaniline,  ethylene 
chloride,  methylaniline,  ethylaniline,  isobutylacetate  and  diphenylmethane. 

It  is  possible  to  compare  with  these  values  of  the  calculated  \c  ,  the  corre- 
sponding values  found  from  capillary  rise,  and  consequently  to  find  proof  for  the 
relationship 


for  only  the  following  liquids:  carbon  disulphide,  cymene,  dimethylaniline, 
diphenylmethane,  ethylaniline,  toluene,  phosphorus  trechloride,  metaxylene, 
methylaniline,  and  mesitylene.  In  the  cases  of  toluene  and  phosphorus  trichloride 
the  agreement  is  practically  perfect  between  the  critical  temperatures  from  drop 
weight  and  capillary  rise.  With  diphenylmethane,  ethylaniline,  cymene,  and 
methylaniline,  a  value  of  tc  at  some  temperature  in  capillary  rise  values  is  always 
to  be  found  which  is  equal  to  the  one  constant  at  both  temperatures  by  drop  weight 
method.  In  the  case  of  methylaniline,  the  large  change  from  9.09°  to  108.5°  when 
compared  with  the  smaller  one  between  108.5°  and  210.8°  would  seem  to  indicate 
error  somewhere,  which  of  course  may  be  due  to  decomposition.  With  dimethyl- 
aniline  the  trend  is  the  same  in  all  results,  although  it  can  hardly  be  said  that  the 
agreement  in  the  capillary  rise  values  is  satisfactory  —  all  this,  including  the  trend, 
may  well  be  due  to  the  decomposition  of  this  liquid,  which  seems  to  be  very  un- 
stable in  pure  condition.  For  cymene  the  mean  of  all  values  from  capillary  rise 
is  395.5,  which  agrees  fairly  well  with  the  constant  drop  weight  value  of  394.7. 
For  metaxylene  the  drop  weight  values  are  constant  but  lower  than  either  set 
found  from  capillary  rise,  but  the  fact  that  capillary  rise  values  do  not  even  agree 
well  enough  with  one  another,  indicates  that  there  is  a  source  of  error  in  capillary 
rise  in  case  of  this  liquid. 


1  Q  „.„ 

•  •       *        •••••*.••,•.••      * 

CONCLUSIONS  ' 

The  results  of  this  research  may  be  summarized  as  follows : 

I.  According  to  the  new  definition  of  the  normal  molecular  weight,  i.  e.,  that 
the  normal  (benzene)  constant    £B    gives  for  the  liquid  a  constant  value  of  t 
independent  of  the  temperature  of  observation,  in  the  relationship 

/(M)  =  £B(^-/-6) 

the  following  liquids  are  to  be  regarded  as  perfectly  non-associated  as  is  benzene 
itself :  brombenzene,  bromine,  ethylidene  chloride,  toluene  phosphorus  trichloride, 
para-,  ortho-,  and  meta-xylenes,  mesitylene,  ethylbenzene,  iodobenzene,  flour- 
benzene,  cymene,  ethylenechloride  methylaniline  ethylaniline,  isobutylacetate, 
carbon  disulphide,  and  diphenylmethane.  In  the  case  of  dimethylaniline  the 
discrepancy  in  the  values  of  tg  is  0.8%,  which  is  much  too  great  for  an  experi- 
mental error,  and  can  only  show  that  the  molecular  weight  is  slightly  abnormal, 
which  could  be  due  to  the  fact  that  the  liquid  is  readily  decomposed. 

II.  Of  the  values  of  te    calculated  for  the  above  liquids,  those  for  brom- 
benzene,   bromine,    ethylidenechloride,    toluene,    phosphorus    trichloride,    ortho-, 
meta-,  and  para-xylenes  agree  excellently  with  the  observed  critical  temperature; 
while  the  disagreement  with  this  for  ethylbenzene  and  iodobenzene  is  around  1%. 

III.  The  agreement  between  the  calculated  values  of  tc  from  drop  weight 
and  those  for  capillary  rise,  with  the  11  liquids  which  have  been  studied  by  that 
method  is  exceedingly  good  for  toluene  and  phosphorus  trichloride.    In  other  cases 
the  mean  of  the  te  from  capillary  rise  agrees  well  with  that  from  drop  weight, 
and  it  is  only  for  mesitylene  and  metaxylene  that  the  values  in  mean   from 
capillary  rise  disagree  with  those  from  drop  weight.    In  the  latter  case,  however, 
this  seems  to  mean  little,  as  the  values  by  two  observers,  although  higher  through- 
out, do  not  agree  even  fairly  with  one  another. 


BIOGRAPHY 

Garabed  K.  Daghlian  was  born  January  11,  1882,  in  Aintab,  Turkey.  He 
graduated  from  Central  Turkey  College  in  1902,  spent  the  year  1906-7  in  graduate 
study  in  Syrian  Protestant  College,  Beiruit,  Syria,  and  attended  Columbia  Uni- 
versity as  a  graduate  student  in  the  faculty  of  Pure  Science,  i909-19il.  He 
received  an  M.A.  from  Columbia  University  in  1910,  and  was  appointed  Uni- 
versity Scholar  in  Physical  Chemistry  for  1910-11,  He  was  art  assistant  and 
instructor  in  Central  Turkey  College,  1902-1909. 


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to  $1.00  per  volume  after  the  sixth  day.  Books  not  in 
demand  may  be  renewed  if  application  is  made  before 
expiration  of  loan  period. 


FEB   29193;> 


757n-8,'31 


FES  29  1932 


22691 6 


